I saw the opamp with single supply 15v. just an inverting configuration.
The funny thing is the there is half-voltage biasing, but just 2.2k across + and - input. What is the logic? Is this a good way to use the single supply?
normal inverting? so output is connected to + terminal and input is connected to -? with 2.2k between them.. hmm what is the size of feedback resistor from output to + terminal? sounds like offset nulling, but try to post the data sheet here, or at least the circuit you ask about.